Method and system for treating oily wastewater

Abstract

The invention relates to a method for treating oily wastewater comprising: pretreating the oily wastewater using at least one of electrocoagulation, flotation and absorbing to produce a pretreated water; and treating the pretreated water using membrane distillation to produce a product water. In another aspect, the invention relates to a system for treating oily wastewater comprising: a pretreatment apparatus for pretreating the oily wastewater to produce a pretreated water, the pretreatment apparatus comprising at least one of an electrocoagulation apparatus, a flotation apparatus and an absorbing apparatus; and a membrane distillation apparatus for treating the pretreated water to produce a product water.

1 . A method for treating oily wastewater comprising:
 pretreating the oily wastewater using at least one of electrocoagulation, flotation and absorbing to produce a pretreated water; and   treating the pretreated water using membrane distillation to produce a product water.   
     
     
         2 . The method of  claim 1 , wherein the oily wastewater is from steam assisted gravity drainage oil recovery process. 
     
     
         3 . The method of  claim 1 , wherein the pretreating comprises electrocoagulation. 
     
     
         4 . The method of  claim 3 , wherein an electrode used in the electrocoagulation comprises iron, steel, aluminum, zinc or magnesium. 
     
     
         5 . The method of  claim 1 , wherein the pretreating comprises active carbon absorbing. 
     
     
         6 . The method of  claim 1 , wherein the pretreating comprises air flotation or natural gas flotation. 
     
     
         7 . The method of  claim 6 , wherein a zeolite introduces air or natural gas during the flotation. 
     
     
         8 . The method of  claim 1 , wherein the pretreating comprises a combination of air or natural gas flotation and electrocoagulation. 
     
     
         9 . The method of  claim 8 , wherein the product water is further treated by active carbon absorbing. 
     
     
         10 . The method of  claim 1 , wherein the pretreated water has a temperature higher than that of the product water. 
     
     
         11 . A system for treating oily wastewater comprising:
 a pretreatment apparatus for pretreating the oily wastewater to produce a pretreated water, the pretreatment apparatus comprising at least one of an electrocoagulation apparatus, a flotation apparatus and an absorbing apparatus; and   a membrane distillation apparatus for treating the pretreated water to produce a product water.   
     
     
         12 . The system of  claim 11 , wherein the oily wastewater is from steam assisted gravity drainage oil recovery process. 
     
     
         13 . The system of  claim 11 , wherein the pretreatment apparatus comprises an electrocoagulation apparatus. 
     
     
         14 . The system of  claim 13 , wherein the electrocoagulation apparatus comprises an electrode made from iron, steel, aluminum, zinc or magnesium. 
     
     
         15 . The system of  claim 11 , wherein the pretreatment apparatus comprises an active carbon absorbing apparatus. 
     
     
         16 . The system of  claim 11 , wherein the pretreatment apparatus comprises an air or natural gas flotation apparatus. 
     
     
         17 . The system of  claim 16 , wherein the pretreatment apparatus comprises a zeolite for introducing air or natural gas. 
     
     
         18 . The system of  claim 11 , wherein the pretreatment apparatus comprises a combination of an air or natural gas flotation apparatus and an electrocoagulation apparatus. 
     
     
         19 . The system of  claim 18 , further comprising an active carbon absorbing apparatus for treating the product water. 
     
     
         20 . The system of  claim 11 , wherein the pretreated water has a temperature higher than that of the product water.